1. Field of the Invention
The present invention relates to a method and related device for reducing data transition of a transmission end in a data transmission interface, and more particularly, to a method and related device that determines whether to encode received data for reducing data transition by feeding back output data to compare with the received data.
2. Description of the Prior Art
A liquid crystal display (LCD) has advantages of low radiation, light weight and low power consumption. Thus, the LCD has gradually replaced conventional cathode ray tube (CRT) displays, and is widely used in various information technology products, such as a notebook computer, a personal digital assistant (PDA), a mobile phone, etc. In general, the LCD utilizes a timing controller to generate data signals corresponding to images being displayed, control signals, and clock signals needed to drive the LCD panel. Then, source drivers of the LCD can perform logic operations to generate driving signals of the LCD panel according to the data signals, the control signals and the clock signals. In order to suppress noise and reduce power consumption, data transmitted from the timing controller to the source drivers through data buses are usually in the form of differential signals. Common data transmission interfaces include a low voltage differential signal (LVDS) interface, a reduced swing differential signal (RSDS) interface, a mini low voltage differential signal (mini-LVDS), and so on.
Since the data transmitted in the form of differential signals alternates between 0 and 1, current signals carried on data lines of the data transmission interface also swing back and forth unceasingly. Thus, harmonics respectively belonging to different frequency bands are easily radiated in the form of electromagnetic waves, resulting in a problem of electromagnetic interference (EMI). Furthermore, with increasing demand for large-size, high-resolution, and high-speed transmission, not only is the number of data lines increased, but also data frequency of the data transmission interface is significantly enhanced, so that the EMI problem becomes more and more serious.
For example, please refer to FIG. 1. FIG. 1 is a schematic diagram of a prior art timing controller 10. The timing controller 10 is utilized for generating data signals corresponding to images being displayed on a display panel 12 and generating control signals and clock signals needed to drive the LCD panel 12. The timing controller 10 employs two LVDS bus receivers 110 and 120 as a data reception interface to receive data, and employs a mini-LVDS bus transmitter 130 as a data transmission interface to transmit the generated control signals, clock signals and image data to source drivers of the LCD panel 12. In this case, data frequency of the mini-LVDS bus transmitter 130 will be 3.6 times that of the LVDS bus receivers 110 and 120, and may be even as high as 270 megahertz when realized in high-resolution applications (such as 1680*1050). At this time, if there still exists unceasing alternation of the transmitted data, or data transition, in the data transmission interface, severe EMI problems will occur, which will affect image quality of the LCD panel 12.
Thus, if the number of data transitions occurring between transmitted data of the data transmission interface can be eliminated, the above-mentioned EMI problems can be improved effectively as well.